Around two thousand years ago, a Greek doctor named Dioscorides described a plant that he considered to be medically useful. It was called ‘crocodilium’, he said, and it was supposed to help people who were splenetic. When boiled and drunk, it ‘causes copious bleeding at the nose’. Other characteristics, apart from the shape of its roots and seeds, and the fact that it grew in ‘wooded places’, were unfortunately obscure.